Hi Scott
Southern Cross did make a fully enclosed pump head as early as 1961 a HD patten the third letter was the stroke length HD-G 15"
BUT SC kept on making the old one when the should not of, that is not good business sense
Everything you buy when new models comes out the old one is finished so you have to update,What would happen to cars if they kept on making the old model years latter when they are trying to sell the new model
SC engines are not that good/modern for the time frame, everyone was using Alloy SC was not and when they tried to play catch up with a V twin 20hp alloy engine which would of been great everybody else had already done it and had a name for themselves
SC started selling in 1974 a Perkins diesel as it was greater HP than their own ED-G engine at the same time frame also started selling Villiers , Briggs & Stratton, 6 cylinder Ford and 2, 3, 4, 6 cylinder Itilian VM diesels just to try and stay in business
Ian